Cuttings work good to and your plants are far ahead.Only just spotted this thread. If those were in my garden, I would collect seed, grow some more, grub out all of the existing plant and clean the whole area. Then grow the new plants on and use them in several places in the garden when they're ready.
Just an idea.
Actually, if we are all supposed to be gardeners, why aren't we collecting seed more to grow our own plants. There's so much more for your money then, and it's not that difficult to do.
big rockpile